External risk intelligence

Attacker can steal control of your systems by compromising the Axios software.

CVE advisorySeverity: CRITICAL (CVSS 9.1)

CVE-2026-42044

A flaw in the Axios library allows attackers to secretly alter data from API responses, potentially leading to unauthorized access or financial manipulation. This widely used tool makes many applications vulnerable.

4Halo Surface Signal

Privilege Escalation

Axios

1.0.0 to before 1.15.1

External exposure likelihood

Halo Surface Signal score for CVE-2026-42044

Axios is a pervasive HTTP client library used in web and Node.js applications to manage API communication. Because it is a standard component for processing JSON responses from internet-facing services and public-facing web applications, the parsing functionality is commonly involved in handling network-reachable data in typical web deployment patterns.

Horizon Alert

Summary of the vulnerability and why it matters

This issue in the Axios HTTP client could allow an attacker to invisibly modify JSON API responses. This could lead to serious consequences like unauthorized access, changes to financial data, or bypassing security checks.

  • Affects applications using Axios.
  • Can alter data received from APIs.
  • Potentially leads to security breaches.

Attack Path

How an attacker could exploit the issue

An attacker can exploit this by injecting a malicious `Object.prototype.parseReviver` function into an application's dependency tree. This allows them to manipulate any JSON API response, enabling actions like privilege escalation or balance manipulation by altering specific data points before they are processed by the application.

  • Requires prototype pollution.
  • Targets Axios JSON parsing.
  • Affects application data integrity.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability in Axios presents a significant risk as it allows for the silent manipulation of JSON API responses, potentially leading to severe security breaches. The widespread use of Axios in web and Node.js applications means that many systems handling network data are susceptible to this type of attack. Attackers would likely find this attractive due to its potential for stealthy and impactful exploits.

  • Prototype pollution is a common exploit.
  • Affects public-facing APIs.
  • No indication of active exploitation.

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

Prioritize updating the Axios library to version 1.15.2 or later to address the critical prototype pollution vulnerability. If immediate patching is not feasible, implement strict input validation and sanitization on all JSON API responses and monitor for suspicious data manipulation patterns.

  • Update Axios to version 1.15.2+.
  • Isolate services using affected Axios versions.
  • Monitor for unauthorized JSON response modifications.

Frequently asked questions

What is Axios and what is it used for?

Axios is a popular HTTP client library for both web browsers and Node.js applications. It's commonly used to make requests to servers and handle responses, especially for applications that interact with APIs to send and receive data.

How does the Axios vulnerability (CVE-2026-42044) work?

This vulnerability is a type of Prototype Pollution, specifically a "Gadget" attack (CWE-915). It allows an attacker to modify the `Object.prototype.parseReviver` function. When Axios parses JSON responses, this modified function can invisibly alter specific data within the response before the application processes it.

What must be true for an attacker to exploit this vulnerability?

An attacker must first achieve prototype pollution within the application's dependencies. It is not triggered if the application does not use the default `transformResponse` function in Axios or if the data being parsed is not in JSON format.

Who should be concerned about CVE-2026-42044?

Developers and organizations using Axios in web applications that process JSON data from external or internal APIs should be concerned. The Halo Surface Signal indicates this is a likely threat due to Axios being a common component for handling network-reachable data in web applications.

What is the first step to address this Axios vulnerability?

The most important first step is to update the Axios library to version 1.15.2 or a later version. This version includes the fix for the prototype pollution vulnerability.

References